This invention relates to a drug delivery device, and more particularly to such a device that is capable of interlabial drug delivery, for example interlabial or peri-labial drug delivery, or can be used as an adjunct in the delivery of drugs.
The female external genitalia includes the interlabial space, located between the inside surfaces of the labia majora and extending past the vestibule of the vagina. Located within this interlabial space are the labia minora, clitoris, urethral orifice, and vaginal orifice. The interlabial space is covered by a thin layer of keratinized epithelium.
A variety of diseases affect the interlabial space in human females. Infectious diseases include vaginitis, herpes simplex virus-2 (HSV-2), human papilloma virus (HPV), syphilis, and candidiasis. Dysplastic and hyperplastic conditions include postmenopausal atrophy, squamous cell hyperplasia, and lichen sclerosus. Precancerous and cancerous conditions include vulvar intraepithelial neoplasia and vulvar carcinoma. These diseases result in serious health problems, including pain, itching, disfigurement and possibly even death.
Currently, therapy for vulvar diseases is delivered either systemically or locally. Examples of systemic therapy include oral acyclovir for HSV-2 infection, and intramuscular penicillin-G for primary syphilis. Local therapy includes a variety of creams, ointments, and solutions containing corticosteroids, antifungal agents, hormones, and other medicinal agents.
Although both forms of therapy have shown favorable effects on many vulvar diseases, both have limitations. Systemic therapy carries the risk of systemic side effects, and the effectiveness of local therapy has been limited by the need for frequent applications, messiness, and poor patient compliance. There is a need, therefore, for a simple and effective approach to local therapy of vulvar diseases. At the same time, there is a need for more efficient, convenient and comfortable systemic administration of drugs, whether or not they are intended for the treatment of vulvar pathologies.
Feminine hygiene pads consisting of various layers of absorbent materials are used primarily to absorb uncontrolled discharges during menstruation. These pads have taken the form of thick elongated feminine napkins which are primarily used during the early stages of the menstrual cycle and narrow absorbent tubes, known as tampons, which are inserted into the vagina and which are used primarily during the latter stages of the menstrual cycle.
The methods and devices of the present invention take advantage of a completely new use of absorbent interlabial pads, namely the administration of therapeutic and diagnostic agents, such as pharmaceutically active agents or diagnostic reagents. It has been found that local and transdermal administration of many different agents can be facilitated by application of the drug to the labia. However, because of the complex and sensitive anatomy of the perineum and associated labial tissue, it has been difficult to administer agents in this fashion. Moreover, the labial and peri-labial area is frequently the site of infection and inflammation (such as that caused by fungal or bacterial infections, such as vaginitis, or exposure to feces or urine). Although topical ointments can be applied to the perineum and labia, such topical administration is often messy and stains undergarments. In addition, intravaginal suppositories leak from the vagina, resulting in loss of some therapeutic efficacy, and discomfort to the subject.
The present invention has solved many of these problem, by providing a system or device for administering agents (such as pharmaceutically active substances or diagnostic reagents), wherein the device is configured to be retained between the labia of a subject. The device either carries a therapeutically or diagnostically effective amount of an agent to be delivered, or is placed interlabially after an agent has been applied, for example to the external genitalia or intravaginally (as with a suppository). In one example, the device includes an interlabial pad, which is retained in the interlabial space for sustained contact with the labial skin and/or vaginal orifice. This sustained contact conforms to the complex external genital and perineal anatomy, without causing additional discomfort. Moreover, the system is able to function as a self-contained transdermal interlabial drug delivery system which targets the delivery of certain medications to the labia and/or vagina, substantially without staining undergarments or inadvertently delivering the drug to the surrounding perineum and thighs. The pad can be retained in the interlabial space, without the use of a supporting garment or adhesive. In particular embodiments, the pad is positioned external to the vaginal orifice, so that it is not retained by insertion into the vagina. However, in other embodiments, a portion of the pad can project at least partially into the vagina for targeted delivery of drug to the intravaginal space.
In another embodiment, the delivery device includes an intravaginal portion and an extravaginal protion. The extravaginal portion can include an interlabial pad that is retained between the labia, and the intravaginal portion (such as a medicated extension or suppository) delivers medication intravaginally.
Although targeted local delivery of active agents is possible, particularly for an agent having low lipid permeability and low transdermal flux, the delivery system can also be used for systemic delivery of pharmaceutical agents through the labial skin, or via vaginal absorption.